Spring loaded side contact



y 1968 J. F. DUFFIELD ET AL 3,383,647

SPRING LOADED SIDE CONTACT Filed Dec. 8, 1965 United States Patent3,383,647 SPRING LOADED SIDE CONTACT Joseph F. Dutlield, Rte. 1,Georgetown, Ontario, and Zdzislaw R. Godziemba-Dambski, Rte. 4, Bolton,Ontario, Canada Filed Dec. 8, 1965, Ser. No. 512,474 Claims priority,application (3Ianada, Sept. 30, 1965,

3 Claims. 61. 339256) ABSTRACT OF THE DISCLOSURE This invention relatesto spring loaded side contacts and in particular it relates to a sidecontact incorporating a helically wound coil spring member.

It is known to use helically wound springs for spring loaded contacts.Of the known contacts of this type most have utilized the interiorcylindrical surface formed by such springs for the reception andelectrical connection with male prongs. It is known to form the helicaltype spring into the form of a toroid and to receive into the centre ofthe toroid a male prong which is making its entry to the toroidtemporarily increases the nominal diameter of the toroid and stretchesthe spring thereby to maintain electrical contact. Again, it has beenknown to use straight helically wound springs embedded in resilientinsulating material whereby the spring is held against a contactingelectrical member not by the resilience of the spring per se but purelyby virtue of the resilience of the supporting insulating material.

In all the above discussed known techniques all have required thatprimary electrical connections to the spring be made by standard wiringmethods, i.e. the use of soldering, crimping or screw devices passingthrough locally formed eyes in the end coils of the springs.

The present invention contemplates the employment of simple helicalsprings that are supported solely at opposite ends thereof by localsupport means in a cooperating body member thereby leaving the centre ofthe spring free to bow when a cooperating contact member is engagedtherewith.

The invention also contemples providing no other electrical connectionwith the helical spring other than its engagement with the abovementioned supports whereby reception of and subsequent deformation by acooperating prong increases the electric-a1 and mechanical connectionbetween the spring and the support. Thus, the invention provides anextremely simple and inexpensive quick connect device which is compactand which during assembly thereof, requires no more than the insertionof the spring into a suitable recess in the body of an insulatedhousing. The invention has particular application in miniatureelectrical connection devices although the principle of the inventionmay be utilized in connecting devices covering a wide range of currentcarrying capacities.

It is a feature of one aspect of the invention to provide a springloaded side contact.

In accordance with the foregoing aspect the invention comprises: anelectrically conducting member including a pair of spring abutmentscoextensive and spaced apart in a selected plane; a coil spring havingits longitudinal axis disposed parallel to said plane and having itsopposite 3,383,647 Patented May 14, 1968 ends restrained againstmovement in a selected direction transverse to said plane by, anddisposed for making elec- .trical contact with, said abutments, saidspring being further disposed for electrical connection with, andresilient deformation in said select d direction at substantially itsmidlength, by the insertion of said male contact inserted into said malecontact receiving aperture.

A preferred embodiment of the invention will now be described wtihreference to the accompanying drawings in which:

FIGS. 1 and 2 show respectively, a plan and side elevation of a springloaded side contact assembly, part of an associated body member, and aportion of a male contact for reception against the side contact.

Referring now to FIGS. 1 and 2, there is shown a portion of a housing 1comprisin a cover 10 and a base 11. The cover 10 and the base 11 areseparable for assembly purposes and held together by means not shown,but which may include the assembly screws in a standard duplexreceptacle. The cover 10 includes a contact guide hole 12 which iscoaxially disposed with a corresponding hole 13 in the base 11. Theunderside of the cover 10 includes a rectangular recess 14 which recessincludes a pair of slots 15 adapted to loosely receive a helical spring3 to be discussed hereinafter. On the underside of the cover 10 there isprovided a longitudinally disposed slot 16 having a width substantiallyequal to the width of the rectangular recess 14. The depth of the slot16 and the aforementioned width of the slot may be selected to providesubstantially free sliding movement to a conducting member 4 to bediscussed hereinafter.

The conducting member 4 includes a strip portion 41 from which ispunched an aperture 42 adapted to receive a male contact member 5 and apair of tabs 43 are formed by locally forming lines of severance andbending portions of the strip 41 as shown. If the male plug 5 hasnonrounded ends, the edges of aperture 42 may be rounded as shown at42'.

The spring loaded side contact as a whole is assembled by placing thespring 3 into the slots 15 in the recess 14, followed by the placementof the conducting member 4 into the slot 16 so that the tabs 43 bearagainst opposite ends of the spring 3. The base 11 is then placed underthe cover 10 thereby to hold the conducting member 4 in position.

In operation, the male contact member 5 is inserted into the contactguide hole 12 until the contact member displaces the centre of thespring 3 outwardly in order to provide a space for the male contact 5.In so doing, the ends of the spring 3 are urged into closer mechanicaland electrical contact with the tabs 43. Further insertion of the malecontact 5 brings it into contact with the sides of the aperture 42 inthe contact conducting member 4 thus, increasing the rigidity andelectrical conductivity between the male contact 5 and the conductingmember 4. When the male contact 5 is fully inserted a portion of it willbe received in the aperture 13 in the base 11.

While the above discussed embodiment provides for the conducting member4 to be a sliding fit within the slot 16 on the underside of the cover10, it will be obvious that the invention will work just as well withoutsuch a sliding fit. However, the pressure of the sliding fit does permitof wider tolerances in the manufacture of either the cover 10, theconducting member 4, the base 11 or the male contact 5. Again, it willbe appreciated that once the male contact 5 has been inserted far enoughto bend the spring 3, electrical connection between the spring 3 and thetabs 43 is increased and that for some applica' tions no furtherelectrical connection is necessary between the male contacts 5 and thesides of the aperture 42 in the conducting member 4. It will beappreciated in the case of this latter embodiment that the conductingmember 4 should be rigidly held within the slot 16 so that the tabs 43are not free to move in a direction away from the male contact 5 duringthe insertion of the latter.

It will be obvious from the foregoing that assembly of the novel springloaded side contact follows the simplest of procedures and requiresmanufacturing tolerances of a substantially low order. The inventionfurther provides an extremely reliable electrical connection bothbetween the inserted male contact and the spring, but also between thespring and the tabs 43. It Will be further appreciated that since thespring 3 is loosely restrained in the slot 15 it is substantially freeto rotate about its axis of generation during portions of the insertionor with drawal of the male contact 5, so that the spring will be subjectto a cleaning action during each insertion or withdrawal and suchcleaning will occur not only at the centre of the spring 3 at whichcomes into contact with the male contact 5 and also those portions ofthe spring 3 which bear against the tabs 43. While the invention hasbeen described with reference to an embodiment including the base 11, itwill be obvious to those skilled in the art that the aperture 13 in thebase 11 could be dispensed with always providing that means are providedfor retaining the conducting member 4 within the slot 16. It isenvisaged that the novel spring loaded side contact will findapplication not only in duplex receptacles and the like, but also in anytemporary terminal connections such as they may be found on domesticelectrical equipment, patch work boards, radio terminal boards, andautomobile electrical equipment.

We claim:

1. An electrical receptacle comprising a fiat strip conductor, a housingencasing said conductor, a transversely spaced pair of tabs struck upfrom an intermediate portion of said conductor strip, a plug receivingand guiding aperture extending through said housing and said stripconductor, said conductor aperture being longitudinally spaced from saidtabs, an elongated coil spring mounted in said housing and restrained bysaid housing from more than limited endwise movement, said spring havingits axis disposed transversely of said conductor, said tabs beingpositioned on one side of said spring and said conductor aperture on theother side of said spring, the end portions of said spring engaging saidtabs, the axis of said conductor aperture passing closely adajacent thecentral section of said spring, whereby a plug contact inserted into theaperture engages and displaces the central section of said springtowards said tabs, making firm electrical contact between said tabs andsaid plug.

2. An electrical receptacle as defined in claim 1, wherein the aperturein said strip conductor is otfset slightly in the direction of said tabsfrom the entry end of the housing aperture, whereby its edge ispositioned to engage a plug inserted into the entry end of the housingaperture and divert it in the direction of said spring cnd tabs.

3. An electrical receptacle as defined in claim 1, wherein said stripconductor is fixedly encased within said housing.

References Cited UNITED STATES PATENTS 1,175,311 3/1916 Sherman 339--2772,153,176 4/1939 Douglas 339-254 2,533,763 12/1950 Cacciotti 3392542,711,524 6/1955 Beaver 339-256 2,775,746 12/1956 Young 339-2562,882,514 4/1959 Krantz 339256 3,032,738 5/1962 Bonanno 339-2563,072,879 1/1963 Crowther 339--253 FOREIGN PATENTS 242,391 11/1925 GreatBritain.

MARVIN A. CHAMPION, Primary Examiner.

PERRY TEITELBAUM, Assistant Examiner.

